Rats!

The Gambian giant pouch rat is the largest rat in the world. Some grow to be the size of raccoons.

Gambian pouched rats are native to Africa. But they have found a new place to call home. The rats, which can grow to be larger than house cats, have been spotted in Grassy Key, an island in the Florida Keys.

More than 10 years ago, an exotic pet breeder allowed eight of the critters to escape. The population of rats began to grow in the wild. Despite efforts to wipe them out, they have survived. According to the U.S. Department of Agriculture, at least a few dozen are running wild.

Gary Witmer is a biologist with the U.S. Department of Agriculture's National Wildlife Research Center in Fort Collins, Colorado. He told Reuters that the large rodents must leave Florida. “They don’t belong here and they need to be controlled,” Witmer said. "They could cause a lot of damage.”

Animal Intruders

HOWARD BURDITT—REUTERS

Rat handler Kassim Mgaza plays with a Gambian giant pouch rat in southern Mozambique. The rats have been trained to find minefields hidden under the ground.

African pouched rats can grow to be up to three feet long and weigh up to nine pounds. They have big ears, dark beady eyes and a long, stringy tail. Their name comes from their hamster-like cheek pouches, which they use to carry food back to their burrows. They usually live in forests, gardens and orchards.

Experts say the rats could damage local ecosystems if they reach mainland Florida. They are omnivores, or animals that eat almost everything, and could compete for food with endangered species. In Zimbabwe, the rats are often blamed for devouring nuts and damaging pea crops. In the Midwest, they have been blamed for spreading disease.

Trapping the Pack

City officials plan to set up 200 traps with cantaloupe, peanut butter and almond extract as bait. The food will contain a deadly zinc phosphide. Wildlife officials predict the rats will die after eating it.

The Centers for Disease Control and Prevention (CDC) hopes to study the rats from Grassy Key. So far, there are no signs of disease. "We're lucky that's the case," Witmer told Reuters. "They sure can bite."